feat(Go-StudyExample):2021/02/09:新增merge源码阅读和单测代码

SourceAnalysisAndTool/mergo@v0.3.11/issue33_test.go

@@ -0,0 +1,37 @@
+package mergo_test
+
+import (
+	"testing"
+
+	"github.com/imdario/mergo"
+)
+
+type Foo struct {
+	Str    string
+	Bslice []byte
+}
+
+func TestIssue33Merge(t *testing.T) {
+	dest := Foo{Str: "a"}
+	toMerge := Foo{
+		Str:    "b",
+		Bslice: []byte{1, 2},
+	}
+
+	if err := mergo.Merge(&dest, toMerge); err != nil {
+		t.Errorf("Error while merging: %s", err)
+	}
+	// Merge doesn't overwrite an attribute if in destination it doesn't have a zero value.
+	// In this case, Str isn't a zero value string.
+	if dest.Str != "a" {
+		t.Errorf("dest.Str should have not been override as it has a non-zero value: dest.Str(%v) != 'a'", dest.Str)
+	}
+	// If we want to override, we must use MergeWithOverwrite or Merge using WithOverride.
+	if err := mergo.Merge(&dest, toMerge, mergo.WithOverride); err != nil {
+		t.Errorf("Error while merging: %s", err)
+	}
+
+	if dest.Str != toMerge.Str {
+		t.Errorf("dest.Str should have been override: dest.Str(%v) != toMerge.Str(%v)", dest.Str, toMerge.Str)
+	}
+}